When this happens the opposing magnetic poles switch places so the magnetic field is flipped.

The pole reversal happens at the peak of each solar cycle as the sun's "inner magnetic dynamo" reorganises itself.

The exact internal mechanism that drives the magnetic shift is not yet entirely understood by researchers, although the sun's magnetic field has been monitored on a daily basis by Scientists at Stanford's Wilcox Solar Observatory.

This will be the fourth such shift that the observatory has monitored.

Throughout the 11 year solar cycle new polarity builds up as 'sunspots' which are areas of intense magnetic activity that appear as blotches near the equator of the sun's surface.

Over a month long period these sunspots disintegrate and the intense magnetic activity migrates from the sun's equator to one of the sun's poles.

According to Hoeksema as the magnetic field moves towards the pole it erodes the existing opposite polarity.

He said: "It's kind of like a tide coming in or going out,"

"Each little wave brings a little more water in, and eventually you get to the full reversal."

As to what effect this may have, scientists said it could be widespread. The sun's magnetic field exerts its influence in a wide space, known as the heliosphere.

The heliosphere stretches well beyond Pluto and is as far reaching as NASA's Voyager probes close to the edge of interstellar space.

During a magnetic flip the sun is also typically at its peak.

Another possible impact is that the sun's altered magnetic field could interact with the Earth's own magnetic field which could increase the number and range of auroras.

It could also have an effect on power distribution grids and GPS satellites.

However the Sun's magnetic 'flip' could also help protect the Earth.

During the reversal the sun's 'current sheet' becomes wavy. The current sheet is a surface that jets outwards from the sun's equator.

A more wavy current sheet acts as a better barrier to deflect cosmic rays which can be a danger to astronauts and space probes.

Some scientists say that cosmic rays can also affect the Earth's climate and level of cloudiness.

It will certainly help those hoping to glimpse the spectacular northern lights.

Scientists won't know for the next three weeks whether the flip is complete.